Feeders presently available for feeding abrasive particles ranging from a size of 3 to 4 inches in diameter down to 1/64 inch to a few thousands of an inch at an elevated temperature must be hard coated or hard faced in the areas exposed to the particles. If such areas are not hard coated or hard faced, they wear out very quickly.
Current hard coatings from a few thousands of an inch to approximately 1/100 inch depend entirely on the hot brinnelling property of the backup metal. For heavy duty, such feeders are limited to use at temperatures less than 1800.degree. F. If a thicker hard facing is used, that is 1/16 to 1/8 inch, the connection between the hard facing and the back of metal is subject to cracking due to thermal stresses at such elevated temperatures. Hence, the hard facing approach likewise has an upper temperature limit of less than 1800.degree. F.
The problem solved by this invention is the construction of a feeder for heavy duty use with a temperature operating range up to about 2300.degree. F. while feeding abrasive particles, and at the same time being practical with the ability to make maintenance repairs with minimum down time.